Blow needle assembly

ABSTRACT

A compact blow needle assembly for a partible mold means extractable through the rear of the mold means in a direction away from the mold axis, which includes a detent mechanism within the mold means extending substantially perpendicular to the blow needle which is readily accessible from the exterior thereof for releasably locking the assembly in place in a bore within the mold means. The mechanism is especially applicable where the mold means includes two or more side by side cavities for simultaneously blowing plural articles.

United States Patent 11 1 Horberg, Jr. et al.

[ Oct. 23, 1973 BLOW NEEDLE ASSEMBLY [75] Inventors: Charles Horberg,Jr., Northbrook; Richard K. Shelby, l-linsdale, both of I11.

[73] Assignee: Monsanto Company, St. Louis, Mo.

[22] Filed: Mar. 24, 1972 [21] Appl. No.: 237,622

52 US. (:1. 425/387, 425/1310. 204 51 1m.c1 ..B29d 23/03 [58] Field ofSearch 425/1910. 204, 387,

[56] References Cited UNITED STATES PATENTS 2,784,452 3/1957 Ruekberg etal. 425/298 X 3,310,834 3/1967 Simpson et al. 425/182 X 5 1970 Chambers425 192 1 1 1970 Adomaitis 425ID1G. 204

Primary Examiner-Richard B. Lazarus Att0rneyl-larold R. Patton et al.

[57] ABSTRACT A compact blow needle assembly for a partible mold meansextractable through the rear of the mold means in a direction away fromthe mold axis, which includes a detent mechanism within the mold meansextending substantially perpendicular to the blow needle which isreadily accessible from the exterior thereof for releasably locking theassembly in place in a bore within the mold means. The mechanism isespecially applicable where the mold means includes two or more side byside cavities for simultaneously blowing plural articles.

25 Claims, 3 Drawing Figures PAIENIEuums ms 3.767350 SHEET 10F 2 FIG!minimums ms sum 2 [IF 2 FIG. 2

' BLOW NEEDLE ASSEMBLY BACKGROUND OF THE INVENTION This inventionrelates to blow molding and more particularly to blow molding systemsutilizing a hollow needle to expand the parison within the blow mold.

Conventional molding machines include a plurality of mold means each ofwhich is made up of opposing mold sections which may be individuallymounted on carrier blocks and arranged to rotate about a central axis ineither a horizontal, vertical or some intermediate plane. The sectionsof each mold means when closed on each other define one or more cavitiesbounded by internal surfaces of the mold sections which are contoured tothe general configuration of an article to be-molded therein. One of themold halves may be provided with a bore in which a hollow blow needle isreciprocably mounted. for puncturing and then pneumatically expanding aclamped off portion of a tubular parison usually formed in the outlet ofan adjacent extruder head. After many molding cycles of such machinery,it frequently becomes necessary to replace a blow needle which may havebecome blunted or broken, as for example, when the thermoplastic of theparison is rather stiff and difficult to penetrate at moldingtemperatures, or perhaps one of the surfaces against which thereciprocating blow needle mechanism slides has become worn and requiresreplacement. In the type of blow molding machine wherein an outerportion of the split mold means moves toward and away from an opposinginner portion in a direction radial to a horizontal shaft carrying armson which such mold means are mounted, the blow needle mechanism in thepast has been located for convenience on the inner, relatively fixedportion of the mold means for simplicity of construction, all as setforth in U.S. Pat. No. 2,784,452. With this and similar types of wheelmolding machines, it is desirable to mount adjacent mold means units asclose as possible to each other in the circumferential direction ofrotation of the wheel in order to keep the waste material betweenadjacent mold means which must be reprocessed at a minimum, and as closeas possible to the wheel axis in the radial direction on the individualarms in order to minimize generation of unbalanced forces duringrotation of the wheel, which can have adverse stuructural implicationson the various machine components. When this type of mountingarrangement is followed, the amount of space in the area adjacent thehub of the wheel for removing the blow needle mechanism from the innerportion of the mold means for any one or more of the previously statedreasons is extremely limited.

Accordingly, in copending application Ser. No. 140,665, filed May 6,1971, and assigned to the assignee of the present invention, it isproposed to remove the blow needle assembly in the opposite direction,i.e., through the parting face of the blow mold. Though this approachfunctions well in the intended manner, the piston carrying the blowneedle reciprocates in the area adjacent the spot where the needleenters the flash cavity of the mold section. This means that the moldsection cannot be cored in this area for circulation of a cooling mediumtherethrough to set the plastic after it is expanded against theadjacent cavity surface area, and consequently the plastic may not becompletely set in that area when the article is ejected from the blowmold. This can extend the blowing cycle or adversely affect thedownstream trimming process for removing the waste flash from thearticle after ejection from the mold.

Though mechanisms for removably positioning blow needles in moldsections are also disclosed in U.S. Pat. Nos. 3,310,834 and 3,513,502,they do not appear to be best suited for a molding environmentrestricted in terms of available space to manipulate the parts of theneedle assembly.

SUMMARY OF THE INVENTION Accordingly, it is an object of this inventionto avoid these prior art deficiencies by providing a novel, compact,quick change blow needle assembly which permits replacing a blow needleor a part of the blow needle piston assembly without removing any of thecomponents of the mold means from their positions on the blow moldingmachine, and which requires a minimum of clearance at the rear of themold to accommodate such removal. 7

Another object of this invention is to provide a simplified blow needleassembly which is self contained within a support block carrying one ofthe blow mold sections.

A further object of this invention is to provide a novel blow needleassembly which occupies a minimum of space in the mold means in which itis mounted and which is releasably held in place by means readilyaccessible from the exterior of the mold.

A particular object of this invention is to provide a blow needleassembly of the type described which is readily removable through therear face of the inner portion of a mold means assembly adjacent thehorizontal axis of a vertically rotating wheel having radially extendingarms on each of which a mold means assembly is mounted.

A further object of this invention is to provide novel needle assemblymounting means which permits extraction of the blow needle assemblythrough the rear face of one of the sections of the mold means in whichit is installed.

Another object of this invention is to provide novel, compact blowneedle assembly retention means especially applicable to a plural cavityblow mold.

Yet an additional object of this invention is to provide such blowneedle assembly retention means for a plurality cavity blow mold bymeans of which individual blow needle assembly units may be selectivelyreleased from their operating positions within themold means.

Other objects of this invention will in part be obvious and will in partappear hereinafter.

These and other objects are accomplished in a molding machine of thetype having split mold means carrying a blow needle'assembly whichincludes a housing for a piston supporting a needle for puncturing andexpanding clamped off portions of a tubular parison by providing theimprovement which comprises a detent BRIEF DESCRIPTION OF THE DRAWINGSIn describing the overall invention, reference will be made to theaccompanying drawings wherein:

FIG. 1 is a vertical, sectional view of apparatus embodying the presentinvention;

FIG. 2 is a partial, sectional view along 2-2 of FIG. 1 illustratingapparatus portions of FIG. 1 ready to be released from assembledposition; and

FIG. 3 is a front view along 3-3 of FIG. 2.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENT Referring now to thedrawings, there is shown in FIG. 1, one station of a multi-stationrotary blow molding machine for forming hollow articles from portions ofa continuously extruding thermoplastic parison. Since such extrusionmeans and thermoplastic parison are conventional to those skilled in theart, as shown in U.S. Pat. No. 2,784,452, they are not shown herein. Astation identical to and immediately adjacent station 10 is depicted inoutline form as 11 in FIG. 1.

In brief, the blow molding machine of which station 10 is a partcomprises a driven, horizontal central shaft carrying a hub to which alarge diameter circular plate is welded. A series of elongatedspoke-like arms extending radially of the wheel axis are in turnfastened to this circular plate, one arm for each mold station.

This structure is relatively conventional as shown in the previouslymentioned U.S. Pat. No. 2,784,452 and is not shown in the drawings. Amold spacer casting 12 (FIG. 1) is provided for each mold station 10 andis secured by suitable fastening members through holes 16 to its radialarm, not shown. Casting 12 includes a support rib l4 and outer platformportion 20.

Means may be provided to resiliently support the mold means of eachstation 10 on the machine, to compensate for any machining descrepanciesin the cam arrangement (not shown) for opening and closing the mold.Such means may comprise a series of coil compression springsschematically illustrated as 22 in FIG. 1, situated in opposing cavitiesin backup plate 24 which is rigidly mounted on platform portion ofcasting l2, and inner mold section support block 26. With thisarrangement, the extent of resilient movement of the inner portion ofthe mold means, (the latter being shown in closed position in FIG. 1) isdefined by 28, which represents the clearance between the underside ofhead 30 of one of a series of shoulder bolts 32, and the opposite topsurface 33 of a surrounding wear bushing 34 situated in cavity 36 inradially stationary backup plate 24. Thus, when the mold means is inopen position (not shown), surface 33 of bushing 34 and the underside ofhead 30 are in abutting relationship as a result of the radially outwardforces generated by springs 22, and a clearance will exist between theopposed, adjoining faces of backup plate 24 and inner mold sectionsupport block 26, which clearance is eliminated as shown in FIG. 1 whenthe mold means is in closed position.

Split mold means 38 are provided at each molding station 10 and includeinner mold half 40 having molding cavity 42 formed therein openingtoward outer mold half 44 the latter being constructed substantiallyidentical to mold section 40 in the portion defining the main bodysection of the article being molded. Each mold section 40 and 44 mayoptionally be formed in two parts, as illustrated in FIG. 1, one partdefining the body of the article being molded and another abutting part39 defining the article finish and waste moile through which the blowair passes in a manner to be described hereafter. Side 46 of inner moldsection 40 which is opposite the side in which cavity portion 42 isformed lies against front face 108 of block 26 in supporting contacttherewith.

Blow needle assembly 48 is provided for split mold means 38 and includeshousing 50 having internal chamber 52 for a piston 54 carrying a hollowneedle 56 situated in a narrow bore formed in inner mold section 40, andcapable of extending into flash holding portion 58 of cavity 42 topuncture and expand successive clamped off portions of a tubular parison(not shown).

A series of channels 96 are formed in mold section 40 and, asillustrated, these channels can extend well into mold part 39 adjacentthe flash holding portion 58 and finish defining section 98 of cavityportion 42. As an important aspect of the invention, the only part ofmold section 40 which is occupied by a part of the blow needle assembly48 is the relatively narrow bore within which bushing 100 is seated, andthrough which blow needle 56 reciprocates. Thus, no compromise need bemade with the cooling capacity of the mold section in order toaccommodate means for removably mounting blow needle assembly 48. As isillustrated in FIG. 1, each of the cooling channels typicallyillustrated as 96 of inner mold section 40 communicate, for example bymeans of inlet and outlet passages 102 and 104 with supply and dischargecooling channels illustrated as 106 in support block 26. Thus, thecooling medium for each mold station 40 is piped into support block 26which in turn feeds and discharges from aligned cooling channels 96 in amold section 40. With this construction, when it is desired to changemold sections 42 and 44 of the mold means 38, for example to form adifferently shaped article on the machine, the cooling medium supply anddischarge lines need not be disturbed since they are associated withsupport block 26 which likewise is not disturbed during a moldchangeover. The newly installed mold section(s) in turn would havecooling channels formed therein in the same manner as illustrated forsection 40 so that such channels would be aligned with the correspondingfeed and discharge openings in the channels 106 in support block 26. Inthis way machine down time for mold changeover is minimized.

As illustrated, outer mold section 44 of mold means 38 may be providedwith cooling channels 45 and mounted on a separate outer mold section insupport block 47 similarly to that for inner section 40.

Blow needle assembly 48 in the illustrated embodiment is situated withina vertical cylindrical bore formed in and extending fully throughsupport block 26, one end of such bore opening to rear side 46 of moldsection 40 and the other end being open to the surrounding atmosphere.To allow for removal of the various components of assembly 48 throughthe rear end of the bore in support block 26, it may be necessary tomachine away minor end portions of backup plate 24 and platform portion20 of mold spacer casting 12 to form cutout sections 60 and 62 thereinwhich act as extensions of the cylindrical bore in support block 26.

Means are provided at the rear ends of housing 50 of blow needleassembly 48 and the bore in support block 26 in which it is confined fordelimiting the forwardmost position of housing 50 in said bore. In theillustrated embodiment, such means comprise an enlargement 64 formed onhousing 50 which seats in an opposite depression in a portion of thebore defining surface in block 26 in the manner generally indicated inFIG. 1. Housing 50 also has internal step 66 at the rear end of internalchamber 52 which delimits rearward movement of piston 54 when surface 68thereof abuts against the opposite horizontal surface of step 66.Peripherally extending slot 70 is formed in the outer surface of housing50 adjacent its rear end which communicates by means of horizontalextension 72 with internal chamber 52 of housing 50 on one side and onthe other side with fluid passage 74 formed in support block 26. Also,when enlargement 64 is seated within the opposite depression in block 26in the manner illustrated in FIG. 1, the forward end of housing 50 isspaced from stop member 76 so as to form channel 78 with surface 80 ofthe bore in support block 26, which in turn communicates with a secondfluid passage 82 in block 26.-The inner surface of channel 78 is definedby cylindrical surface 84 of piston 54 when the latter is in itsforwardmost position in the bore of block 26, as illustrated in FIG. 1.

Stop member 76 has an annular projection 86 thereon for cooperating withan opposing depression in the surface of the bore to define a seat formember 76 in the forwardmost end of the bore. Stop member 76 serves todelimit the advancing movement of piston 54 in housing 50 by acting asan abutment for the former when it is propelled toward cavity 42 in amanner to be described. Stop member 76 has a central cylindrical passageextending through it which is in alignment with 'a correspondingextension thereof in mold section 40 when member 76 is in seatedposition and through which needle 56 reciprocates during functioning ofthe blow needle assembly.

Hollow blow needle 56, is preferably formed of a ductile metal with aflared rear end portion 88 which is press fit into place between atapered surface portion of a cavity formed in piston 54 and an opposingmatching surface of a nose portion 90 on hollow piston rod 92 which fitswithin the cavity in piston 54 and extends rearwardly thereof. Means areprovided on rod 92 for forcing nose portion 90 into the cavity in piston54 with flared end portion 88 of hollow needle 56 situated therebetweenso as to deform the ductile metal of needle 56 outwardly between noseportion 90 and the opposing surface of the cavity and thus frictionallyengage flared end 88 between the two mating parts. In the illustratedembodiment, these means comprise an enlargement 94 formed on rod 92which may be in the form of a multi-sided head so as to be compatiblewith a.

wrench to assist in advancing hose portion 92 into flared end 88 in thejust described manner. Thus, to remove a needle from its position withinpiston 54 after blow needle assembly 48 has been removed from itsposition in the bore in the support block, it is merely necessary toback rod 92 off with a quick turn of a wrench applied on enlargement 94so as to release needle 56 from its position thereon. A second or newneedle is then dropped into place through the axial bore in piston 54with its flared end 88 to the rear. Rod member 92 is then forced intothis flared end of the new needle such that it is forced outwardly intofrictional engagement with the surface of nose portion 90 and theopposite surface of the cavity formed in piston 54.

O-ring seals typically illustrated at 114 in FIG. 1 may beprovidedbetween the various sliding parts of assembly 48 and surface portions ofthe bore in which it is situated.

As an important feature of the present invention, means are provided forreleasibly locking housing 50, and consequently the remaining portionsof blow needle assembly 48 within housing 50, in place in the confiningbore in support block 26 of mold means 38. These means comprise a detentmechanism generally indicated as 118 in FIG. 2 within mold means 38accessable from the exterior thereof and extending substantiallyperpendicular to needle 56. A crosswise bore 119 extends fully throughblock 26 of mold means 38 at right angles to the vertical bore withinwhich blow needle assembly 48 is confined, and an elongated cylindricalrod 120 is positioned therein. Means 132 comprising compression spring134 between collar 136 seated against a shoulder in bore 119 andsecuring nut 138 threaded on the end of rod 120 releasably biases rod120 to the rear in the direction of arrow 140 in FIG. 2 so as to drawcollar 122 against face 126 of support block 26. Collar 122 is fastenedon one end of rod 120 by means of pin and extends outwardly of verticalface 126 of support block 26. Collar 122 may have a knob 128 thereonwith a knurled surface to aid in rotating shaft 120. It should berealized that face 126 of block 26 extends vertically of the axis of theblow molding machine at each mold station and consequently any partprotruding therefrom, such as a knob 129, is readily accessible incomparison with the relatively confined area at right angles to face 126adjacent the axis of the molding machine i.e., in clearances 60 and 62in FIG. 1. Rod 120 when in place in bore 119 has a flat portion 130milled in its surface which intersects the vertical bore within whichhousing 50 is confined in the manner illustrated in FIG. 2. Housing 50of assembly 48 in turn has a matching slot or flat 128 formed on itsouter surface adapted to lineup opposite that in rod 120 when the latteris in position in bore 119. Thus, when it is desired to release blowneedle assembly 48 from its self contained position in the verticalconfining bore in support block 26, freely accessible knob 128 is merelyrotated such that flat surface 130 on rod 120 lines up with the oppositeflat'surface 129 on the outside of housing 50, whereupon housing 50,piston 54, rod member 92 and attached hollow needle 56 are free to fallout of support block. 26 through cutout portions 60 and 62 in backupplate 24 and platform portion 20 respectively into the hand of anoperator. No further dismantling of the piston and housing is necessaryin order to expose the needle to be replaced.

Rod 92 is merely backed out of its position within the piston, a newneedle dropped into place and the rod forced against the piston by meansof projection 94, the piston inserted within the housing and the housinginserted within the vertical bore in the support block in order tocomplete reassembly. In similar manner, a piston, or for that matter anew housing, may be readily replaced. After the housing is againsituated within its vertical confining bore in block 26, knob 128 isturned so that a portion of the cylindrical surface of rod 120 issituated within the flat 128 on housing 50 to securely fix the housingin place within the support block. In this manner, it should be noted,that a blow needle assembly 48 may be replaced without in any waydisturbing the mold section 40 within which it is operable, stop member76 remaining in place because of the way in which it is seated withinthe bore by means of projection 86 thereon.

As another feature of the invention, a second mold cavity schematicallyillustrated in part as 140 in FIG. 2, may be provided as part of thesingle mold means 33, cavity 140 being situated adjacent to andextending parallel with cavity portion 42. A second blow needle assemblyconstructed exactly the same as that for the just described assembly 48may be provided in a second vertical confining bore in support block 26.With such construction, detent mechanism 118 is extended so as to alsofunction with the second assembly by providing a portion generallyindicated as 144 for cooperation with second housing 146 in the samemanner as previously described for assembly 48. With such construction,pin 150 can be used as an indicator of the position of flat surfaces 130and 152 of rod 120 with respect to the corresponding opposed flatsurfaces on housing 50 and 146 respectively situated within block 26. Bymisaligning flat surface portions 130 and 152 on rod 120 as indicated inFIG. 2, one or the other of housings 50 and 146 may be preferentiallyreleased from confinement within the support block. Thus, by turningknob 129 to the position illustrated in FIG. 2, in which pin 150 isprojecting vertically upward, the front housing 50 is in its releaseposition, whereas housing 146 is still locked in place. By rotating knob129 90 degrees to the left from the position shown in FIG. 2, asillustrated at 142, both housings 50 and 146 are locked in place,whereas further rotation through an additional 90 to position 143 willplace rear housing 146 in release position while front housing 50 willstill be locked in place. Thus, one or the other of housings 50 and 146may be selectively released from their positions within the verticalbores of support block 26. Suitable indicator markings may he formed onface 126 of block 26 to indicate the positions of the various parts. Pin124 on the surface of rod 120 is movable within end milled slot 125 inblock 26 to limit rotation of rod 120 to 180.

As yet another feature of the invention, a loading fixture 154 may beprovided to aid in inserting a blow needle assembly in its vertical borein support block. Such a loading fixture may be desirable since cut outportions 60 and 62 at the rear of the mold means through which theassembly must pass as it is being inserted in the block, as mentioned,are relatively inaccessible, and it is necessary that the slot portionof the cylindrical housing be in proper circumferential position inorder that it mayline up with the opposed matching flat on the outersurface of the rod of the detent mechanism, or otherwise the needleassembly cannot assume its fully seated position within the verticalbore. Such aligning might be especially difficult when the inner moldsection 40 is not to be disturbed during replacement of a blow needle.Loading fixture 154 has means thereon for cooperating with the rear endof a housing 50 to facilitate insertion of the latter into its verticalbore in thesupport block. Such means in the illustrated embodimenthomprise a head portion 155 at the top fixture 154 with a protrudingboss 156 thereon having a diameter such that it may be frictionallyengaged in recess 158 in the base of each housing 50. Means may furtherbe provided on housing 50 and a surface portion of the vertical bore inwhich the housing is to be mounted for orienting slot 128 with respectto the opposite flat surface on rod 120 of the detent mechanism. Theseorienting means in the illustrated embodiment comprise a projection orlug 161 on the surface of the annular depression at the rear end of thevertical bore in block 26 designed to fit within a matching U-shapedslot or notch in enlargement 64 of housing 50. Thus, to insert anassembly 48 in the confining bore of block 26, boss 156 of fixture 154is frictionally engaged in recess 158 of housing 50. The housing mountedon the fixture is then inserted into the vertical bore in the supportblock and the fixture rotated until projection 161 seats in the opposingU-shaped notch in enlargement 64. This then means that the flat surface130 on the rod is lined up opposite the slot or flat surface on thehousing, and that the housing is in its fully advanced position withinthe bore. Knob 129 is then turned to bring a cylindrical portion of rod120 within the slot and accordingly lock housing 50 in place.

In operation, a portion of an extruding parison (not shown) ispositioned between opposing inner and outer mold sections 40 and 44 ofmold means 38 while such sections are separated from each other aboutmold parting line 162. The outer portion of mold means 38 is then causedto close on the inner portion to assume the position illustrated in FIG.1 with the parison portion clamped therebetween, all in a generallyknown manner as described in US. Pat. No. 2,784,452. As mold station 10continues its peripheral movement in the direction of arrow 1 12(FIG. 1) around the molding machine, the clamped off parison portion isexpanded outwardly against the surfaces of the mold cavity to form, inthe illustrated embodiment, an elongated tubular article.

With respect to blow needle assembly 48 by means of which such expansionis accomplished, hollow needle 56 is initially in its retractedposition, as illustrated by the phantom lines 116 in FIG. 1 while theparison portion is being clamped in place between the opposing moldsections. After this is accomplished, pressured air from a suitablesource and by means of suitable valving well known to those skilled inthe art and not shown, is admitted through passage 74 in support block26, slot and extension 72 in housing 50 and then against the undersideor rear face 68 of piston 54 so as to cause the latter to advance incavity 52 of housing 50. At this point, air cannot enter the hollowinterior of needle 56 since corss passage 164 is still rearward ofextension 72 in the housing. Such advancing movement of piston 54 willcause the sharp leading end of needle 56 to penetrate the wall of theclamped parison and to eventually assume the position illustrated inFIG. 1. At this point, cross passage 164 is aligned opposite extension72 and pressurized air accordingly can enter the hollow interior ofneedle 56 and eventually exit into the cavity of the blow mold to expandthe parison portion outwardly to form the article. By delayingintroduction of the expanding air into the clamped parison in thismanner, penetration is initially carried out before expansion. Thus,collapse of the wall of the parison towards the mold parting line as aresult of air pressure acting against it is avoided, which wouldotherwise occur if the air were allowed to flow into the interior of theneedle at the same time the latter was attempting to penetrate theparison wall. After the plastic of the formed article has been set bythe cooling medium flowing through channels 45 and 96 in the moldsections, the valving associated with passage 74 in support block 26 isactuated so as to terminate the flow of air into the mold and to ventpassage 74 to atmosphere. This will .will continue. Such rearwardmovement of the needle may be facilitated by introducing air by suitablevalving (not shown) into passage 82 in block 26 and channel 78 so as toact against surface 166 which is the horizontal portion of a step formedin the leading end of piston 54, thus driving the latter to the rearuntil surface 68 abuts against surface 168 of internal step 66 ofhousing 50. When this occurs, enlargement 94 on rod 92 is preferablysuspended within pocket 93 in chamber 52, since if rearward movementwere interrupted by bottoming out on enlargement 94, the friction fit ofthe needle within the piston might undesirably be loosened and theneedle could be prematurely released from its association with thepiston. The mold means 38 may then be opened and the article ejectedfrom the molding cavity by suitable conventional knockout meansassociated with channel 170 in the outer section 44 of the mold means ina conventional manner, not shown but well known to those skilled in theart. Mold station is then rotated beneath the extrusion nozzle to acceptthe next parison portion to commence a new cycle.

It should be noted that after the detent mechanism 118 is aligned in themanner previously described to allow ejection of a blow needle assembly48 from its position within the support block, that such ejection can beaided by admitting quick blasts of pressurized air through secondpassage 82 in block 26 so as to act against ledge 172 of the unlockedhousing 50, and thus project it to the rear and out of the verticalbore.

The above description and particularly the drawings are set forth forpurposes of illustration only and are not to be taken in a limitedsense.

Various modifications and alterations will be readily suggested topersons skilled in the art. It is intended,

therefore, that the foregoing be considered as exemplary only and thatthe scope of the inventionbe ascertained from the following claims.

What is claimed is:

1. A molding machine of the type having split mold means carrying a blowneedle assembly which includes a cylindrical housing mounted in a borein the mold means having an internal chamber for a piston carrying aneedle for puncturing and expanding clamped off portions of a tubularparison wherein the improvement comprises a cylindrical detent mechanismfor releasably locking said housing in place within the bore, saidmechanism extending into the mold means substantially perpendicular tosaid needle and being accessible from the exterior thereof, a portion ofthe cylindrical surface of said mechanism lying within a slot in thesurface of said housing when said housing is locked within the bore,said cylindrical detent mechanism having a flat surface for cooperatingwith said slot to permit ejection of the housing from the bore when thedetent mechanism is in the housing release position.

2. The apparatus of claim 1 including opposing means at the rear end ofthe housing and bore for limiting the forwardmost position of thehousing in the bore.

3. The apparatus of claim 1 wherein said housing has a peripherallyextending slot in its outer surface communicating through the wall ofthe housing with the internal chamber and with a fluid passage in saidmold means.

4. The apparatus of claim wherein the needle is formed of a ductilemetal and has a flared end portion press fit between a tapered surfaceof a cavity formed in the piston and .an opposing matching surface of anose portion of a hollow rod extending from the piston.

5. The apparatus of claim 1 including a loading fixture having meansthereon for cooperating with the housing to facilitate insertion of thehousing into the bore.

6. The apparatus of claim 1 wherein said split mold means carries asecond blow needle assembly substantially identical to and mountedparallel to said first mentioned blow needle assembly, said detentmechanism having a second cylindrical surface portion and flat surfacefor cooperating with the housing of the second assembly in the samemanner as said first mentioned cylindrical surface portion and slot.

7. The apparatus of claim 2 including a stop member at the forwardmostend of the bore for delimiting advancing movement of the piston in thehousing.

8. The apparatus of claim 2 including a step at the rear end of theinternal chamber delimiting rearward movement of the piston in thehousing.

9. The apparatus of claim 2 wherein the housing and stop member arespaced apart within the bore to form a channel with the surface of thebore communicating with another fluid passage in the mold means.

10. The apparatus of claim 4 including means on the rod for forcing thenose into the cavity with the flared end portionof the needletherebetween.

11. The apparatus of claim 5 wherein said means for cooperating with thehousing is a head portion at the top of the fixture having a bossthereon adapted to be received in a recess in the base of the housing.

12. The apparatus of claim 9 wherein the piston has a step in itsforward end facing and defining the inner surface of said channel whenthe piston .is in its forwardmost position in the chamber.

13. The apparatus of claim 11 including means on said housing andsurface of the bore for orienting the slot on the housing with respectto the flat surface of the detent mechanism.

14. The apparatus of claim 13 wherein said orienting means comprises amatching lug and U-shaped notch.

15. A molding machine of the type having split mold means which includesa mold half having a molding cavity formed therein opening through oneside of said half, a flat block in supporting contact with the sideopposite said one side of the mold half and a blow needle assembly whichincludes a housing having an' internal chamber for a piston carrying aneedle extending through said mold half for puncturing and expandingclamped off portions of a tubular parison within said molding cavitywherein the improvement comprises a bore in said block entirelycontaining said housing and an elongated detent mechanism extendingthrough a substantial portion of said block in a direction perpendicularto said needle and being accessible from the ex terior thereof, saidmechanism coacting with a surface of said housing for releasably lockingsaid housing in place within said block.

16. The apparatus of claim 15 wherein said mold half includes a secondmolding cavity situated adjacent and parallel to said first mentionedcavity and including a second blow needle assembly in said block forsaid second cavity, said detent mechanism having a portion thereof whichcooperates with the housing of said second assembly in the same manneras for the housing of said first mentioned assembly.

17. The apparatus of claim 15 including a stop member seated in theblock at the forward end of the core containing the housing, said stopmember having an axially extending passage formed therein through whichsaid needle reciprocates.

18. The apparatus of claim 15 wherein said mold half is formed in twosections.

19. The apparatus of claim 15 including a loading fixture for saidhousings having means thereon for cooperation with said housings tofacilitate insertion into the bores in the flat block.

20. The apparatus of claim 15 wherein the bore in the block containingthe housings is open to atmosphere at the end remote from the mold half.

21. The apparatus of claim 15 including channels in said mold halfimmediately adjacent the area through which the needle enters the moldcavity.

22. The apparatus of claim 16 wherein said detent mechanism comprises acylindrical rod situated within a bore extending through said block atdegrees to and intersecting the bores containing said housings.

23. The apparatus of claim 16 wherein said rod has non-aligned flatsurfaces formed thereon at the points where said rod containing boreintersects the housing containing bores.

24. The apparatus of claim 23 including means coacting with a surfaceportion of said rod containing bore for resiliently holding said rodtherein.

25. The apparatus of claim 24 including means outside of said blockconnected to one end of said rod for indicating the position of saidsurfaces with respect to the coacting housing surfaces within the block.

* i i i UNITED STATES PATENT OFFICE (5 69) CERTIFICATE OF CORRECTIONPatent No. 3, 767, 350' D t d October23, 1973 I mg Charles Horberg, Jr.and Richard K. Shelby It is certified that error appears in theabove-identified patentand that said Letters Patent are hereby correctedas shown below:

Column 8, line 45, after "since" delete"corssand insert cross -o ICo1urnn'1 O in Claim 4, after "claim" insert l Signed ar d sealed this5th day of March 197L (SEAL) Attest:

EDWARD M.FLETCHER,JR. C. MARSHALL DANN Attesting Officer Commissioner ofPatents I

1. A molding machine of the type having split mold means carrying a blowneedle assembly which includes a cylindrical housing mounted in a borein the mold means having an internal chamber for a piston carrying aneedle for puncturing and expanding clamped off portions of a tubularparison wherein the improvement comprises a cylindrical detent mechanismfor releasably locking said housing in place within the bore, saidmechanism extending into the mold means substantially perpendicular tosaid needle and being accessible from the exterior thereof, a portion ofthe cylindrical surface of said mechanism lying within a slot in thesurface of said housing when said housing is locked within the bore,said cylindrical detent mechanism having a flat surface for cooperatingwith said slot to permit ejection of the housing from the bore when thedEtent mechanism is in the housing release position.
 2. The apparatus ofclaim 1 including opposing means at the rear end of the housing and borefor limiting the forwardmost position of the housing in the bore.
 3. Theapparatus of claim 1 wherein said housing has a peripherally extendingslot in its outer surface communicating through the wall of the housingwith the internal chamber and with a fluid passage in said mold means.4. The apparatus of claim 1 wherein the needle is formed of a ductilemetal and has a flared end portion press fit between a tapered surfaceof a cavity formed in the piston and an opposing matching surface of anose portion of a hollow rod extending from the piston.
 5. The apparatusof claim 1 including a loading fixture having means thereon forcooperating with the housing to facilitate insertion of the housing intothe bore.
 6. The apparatus of claim 1 wherein said split mold meanscarries a second blow needle assembly substantially identical to andmounted parallel to said first mentioned blow needle assembly, saiddetent mechanism having a second cylindrical surface portion and flatsurface for cooperating with the housing of the second assembly in thesame manner as said first mentioned cylindrical surface portion andslot.
 7. The apparatus of claim 2 including a stop member at theforwardmost end of the bore for delimiting advancing movement of thepiston in the housing.
 8. The apparatus of claim 2 including a step atthe rear end of the internal chamber delimiting rearward movement of thepiston in the housing.
 9. The apparatus of claim 2 wherein the housingand stop member are spaced apart within the bore to form a channel withthe surface of the bore communicating with another fluid passage in themold means.
 10. The apparatus of claim 4 including means on the rod forforcing the nose into the cavity with the flared end portion of theneedle therebetween.
 11. The apparatus of claim 5 wherein said means forcooperating with the housing is a head portion at the top of the fixturehaving a boss thereon adapted to be received in a recess in the base ofthe housing.
 12. The apparatus of claim 9 wherein the piston has a stepin its forward end facing and defining the inner surface of said channelwhen the piston is in its forwardmost position in the chamber.
 13. Theapparatus of claim 11 including means on said housing and surface of thebore for orienting the slot on the housing with respect to the flatsurface of the detent mechanism.
 14. The apparatus of claim 13 whereinsaid orienting means comprises a matching lug and U-shaped notch.
 15. Amolding machine of the type having split mold means which includes amold half having a molding cavity formed therein opening through oneside of said half, a flat block in supporting contact with the sideopposite said one side of the mold half and a blow needle assembly whichincludes a housing having an internal chamber for a piston carrying aneedle extending through said mold half for puncturing and expandingclamped off portions of a tubular parison within said molding cavitywherein the improvement comprises a bore in said block entirelycontaining said housing and an elongated detent mechanism extendingthrough a substantial portion of said block in a direction perpendicularto said needle and being accessible from the exterior thereof, saidmechanism coacting with a surface of said housing for releasably lockingsaid housing in place within said block.
 16. The apparatus of claim 15wherein said mold half includes a second molding cavity situatedadjacent and parallel to said first mentioned cavity and including asecond blow needle assembly in said block for said second cavity, saiddetent mechanism having a portion thereof which cooperates with thehousing of said second assembly in the same manner as for the housing ofsaid first mentioned assembly.
 17. The apparatus of claim 15 including astop member seated in the block at the forward end of the borecontaining the housing, said stop member having an axially extendingpassage formed therein through which said needle reciprocates.
 18. Theapparatus of claim 15 wherein said mold half is formed in two sections.19. The apparatus of claim 15 including a loading fixture for saidhousings having means thereon for cooperation with said housings tofacilitate insertion into the bores in the flat block.
 20. The apparatusof claim 15 wherein the bore in the block containing the housings isopen to atmosphere at the end remote from the mold half.
 21. Theapparatus of claim 15 including channels in said mold half immediatelyadjacent the area through which the needle enters the mold cavity. 22.The apparatus of claim 16 wherein said detent mechanism comprises acylindrical rod situated within a bore extending through said block at90 degrees to and intersecting the bores containing said housings. 23.The apparatus of claim 16 wherein said rod has non-aligned flat surfacesformed thereon at the points where said rod containing bore intersectsthe housing containing bores.
 24. The apparatus of claim 23 includingmeans coacting with a surface portion of said rod containing bore forresiliently holding said rod therein.
 25. The apparatus of claim 24including means outside of said block connected to one end of said rodfor indicating the position of said surfaces with respect to thecoacting housing surfaces within the block.